What does the $@ represent in a bash script?

danielj28 · 12-18-2007, 02:46 PM

I'm new to reading (and writing) bash scripts and I can't find any documentation for what the $@ parameter/variable represents and what value it receives. Please advise. Thanks.

pwc101 · 12-18-2007, 03:18 PM

Quote:

Originally Posted by man bash

@ Expands to the positional parameters, starting from one. When the
expansion occurs within double quotes, each parameter expands to a
separate word. That is, "$@" is equivalent to "$1" "$2" ... If
the double-quoted expansion occurs within a word, the expansion of
the first parameter is joined with the beginning part of the orig-
inal word, and the expansion of the last parameter is joined with
the last part of the original word. When there are no positional
parameters, "$@" and $@ expand to nothing (i.e., they are
removed).

It means each argument supplied to the script from the command line:

Code:

pwc101@linux:> ./myscript argument_1 argument_2

$@ represents argument_1 and argument_2 in that example, which can be individually referenced as $1 and $2.

See http://db.ilug-bom.org.in/Documentat...es.html#APPREF for more info.

danielj28 · 12-18-2007, 07:37 PM

for the help!

PTrenholme · 12-18-2007, 07:51 PM

On most distributions the info command (in a terminal window) may be used to display information about a command. Did you try info bash?

If you're not familiar with the info command, try info info for an explanation.

chrism01 · 12-18-2007, 11:56 PM

The nice version of the manual: http://www.tldp.org/LDP/abs/html/int...es.html#APPREF